A case of open skull fracture, subdural hematoma, and brain contusion complicated by traumatic brain injury-associated coagulopathy caused by a lawn trimmer; A case report

Penetrating head injury is less common than blunt head injury in Japan but causes devastating complications and requires prompt surgical intervention. However, not all penetrating head injuries are apparent on arrival. We herein present a case of a 74-year-old male who lost his balance on a steep hillside and fell on an active lawn trimmer with rotating circular blades, which hit his face. On arrival, the patient was alert and conscious, but was unable to recall the accident. His vital signs were stable and motor functions were normal. The patient had a large laceration ranging from the right lower eyelid to the back of the right auricle. The wound appeared to be superficial with no apparent bone fragments or exposure of the cerebrum. However, trauma CT pan-scan revealed a right temporal bone fracture with multiple skull fragments scattered inside the cranium, and a right temporal lobe contusion. The patient became agitated in the CT suite, followed by a decreased level of consciousness. By the time the patient was rushed back to the emergency room, he was unconscious with minimal respiratory effort, decreased blood pressure, and anisocoria. Blood tests showed evidence of traumatic brain injury-associated coagulopathy. The present case demonstrates how penetrating head injury caused by lawn trimmers may appear subtle in physical examination. The present case also serves as a stark reminder that patients with a high-risk injury or amnesia should undergo trauma CT pan-scan as soon as possible and under-triage of these patients may have devastating consequences.